The mechanism of enzyme secretion is studied using as models the formation and secretion of invertase by the eukaryote yeast (Saccharomyces) and of penicillinase by the prokaryote Bacillus licheniformis. The subunit structures of the mannanprotein form of invertase and of the internal carbohydrate-free enzyme will be compared to clarify their biosynthetic relationship. Also immunochemical procedures will be used to search for inactive subunits or precursors of invertase in a series of invertase-negative mutants or in cells whose production of invertase has been halted by preventing the glycosylation step. The antibiotic tunicamycin which appears to inhibit specifically glycoprotein synthesis, perhaps at the actual transfer stage, will be utilized to examine the nature of the glycosylation process. Characterization of the lipophilic-membrane bound penicillinase will be completed by determining the primary sequence of the phospholipopeptide moiety terminating in phosphatidyl serine. An in vitro penicillinase synthesizing system has been developed. The nature of the penicillinase produced and especially the identity of the initial gene product will be examined. Localization of the membrane-bound penicillinase on protoplasts and on intact cells will be attempted by immunological electron microscopy procedures.